Normally when you press the power button, your HP computer goes through a procedure called the BIOS (Basic Input/Output System) and then loads the operating system. In some cases your computer may automatically restart itself just as the operating system is finished loading, which creates an endless boot loop and prevents you from opening any programs. Resolving a boot loop is handled in several different ways, depending on which software problem originally caused the loop.
Your HP's operating system automatically downloads new updates, which are installed while the computer boots up. If the data failed to download properly the operating system may become stuck in a restart loop. Fixing the problem requires using the system restore feature to revert to an earlier state. Tap "F8" while the computer is restarting and select the "Safe Mode" option, and then open the "System Restore" feature in the "Start" menu. Select a restore date to load to a previous point before the updates were installed.
As your computer goes through the boot process it first loads the BIOS program to check the status of all its hardware devices. The operating system may fail to fully boot and continuously restart if the BIOS boot order options aren't set correctly. To access the BIOS menu, tap "F2" while the computer is restarting. Scroll to the "Boot" tab and tap "F5" to restore the settings to their factory defaults and then exit the BIOS menu.
The Microsoft Windows operating system installed on your HP computer includes an option to automatically restart if certain software problems are detected. If the operating system fails to realize the problem has been resolved, it will continue to reboot repeatedly. To access the restart setting, right-click the "Computer" icon in the "Start" menu and choose "Properties." Open the "Advanced System Settings" window and click the "Settings" button under the "Startup" heading. Turn off the restart feature by un-checking the "Automatically Restart" box.
Corrupt Operating System
Your operating system may become corrupted if registry values are deleted or you experience a serious virus infection. If the operating system restarts repeatedly you won't be able to reinstall Windows normally by using the recovery CD included with the computer. Instead you need to access the hard drive's built-in recovery partition by tapping "F11" while the computer is restarting. Reinstall the operating system by clicking the "System Recovery" button and following the on-screen installation prompts.